Film forming formulation and composition thereof

ABSTRACT

A film forming formulation is provided that includes reaction products of phosphoric acid with a strained ring alkoxy silane. The phosphoric acid and the strained ring alkoxy silane are present in a molecular ratio of from 0.9-3.3:1. The film formulation also includes an aqueous solvent. A mold release coating composition is also provided that includes the film forming formulation, a reactive release agent, a base, and an aqueous solvent.

RELATED APPLICATIONS

This application is a divisional application of U.S. Non-provisionalapplication Ser. No. 16/515,746 filed 18 Jul. 2019, that in turn claimspriority of U.S. Provisional Application Ser. No. 62/700,467 filed 19Jul. 2018; the contents of which are hereby incorporated by reference.

FIELD OF THE INVENTION

The present invention in general relates to resinous reaction productsuseful for a variety of applications including adhesion to varioussubstrates; and in particular to a film forming formulation of reactionproducts of phosphoric acid with a strained ring alkoxysilane in anaqueous solvent, and a mold release coating composition containing thefilm forming formulation.

BACKGROUND OF THE INVENTION

Coating compositions containing organic resins are in wide use. Thereare myriad of compositions produced by dissolving one or more filmforming resins in organic solvent or by blending various emulsified filmforming resins in semi-aqueous or fully aqueous “mediums”. Glycidoxyfunctional film formers have been utilized as reactive portions of manyfilm forming resin systems and formulations for many decades over thepast century. Glycidoxy functional film formers have been used topositively impart many attributes to a variety of substrates includingiron, steel, aluminum, glass, plastics and the like.

Unfortunately, many of the prior art glycidoxy functional film formershaving handling concerns. Thus, there is a need for film formingformulations and compositions thereof that are not endocrine disruptingand avoid the inclusion of hazardous solvents that are deleterious tothe environment. Furthermore, many of the prior art glycidoxy functionalfilm formers require polymerization. Polymerization requires significantenergy input as it utilizes reaction equipment, heat, catalysts,condensation, and further entails recovery of potentially hazardousbyproducts. Due to the significant energy input requirements and theproduction of potentially hazardous byproducts, polymerization furthercompounds the hazards to both human health and the environmentassociated with many of the prior art glycidoxy functional film formers.Film forming formulations and compositions thereof that avoid thesehazards to human health and the environment are therefore highlydesirable.

The use of phosphoric acid as a modifier of glycidoxy functional filmformers is well known and has found widespread use over many decades inthe past century. Phosphoric acid has been used as a catalyst forsolvent based “epoxy” and “epoxy-phenolic” coating compositionsincluding without limitation the interior and/or exterior coatings forpipes (utilized to convey materials), exterior can coatings, andinterior can coatings. Such solvent based “epoxy” and “epoxy phenolic”coating compositions are also hazardous to the environment and humanhealth as they often contain or are themselves endocrine disrupting(both the epoxy and the phenol precursors).

U.S. Pat. No. 4,801,628 (Ashing et al.) discloses non-water dispersible,oxirane-defunctionalized, etherified, phosphoric acid esters of epoxyresins for use as varnishes (clear) or white enamels for drawn andironed beer and beverage containers. Phosphoric acid reaction productsof “oxirane” (glycidyl) resins are prepared in a water soluble, solventbase containing butyl cellosolve and/or butanol. The oxirane resinsutilized are either the diglycidyl ether of bisphenol A (DGEBA) orreaction products of DGEBA with bisphenol A (BPA). Both the DGEBA andBPA are known endocrine disruptors.

Given the state of the prior art, there exists an unmet need for a filmforming formulation that avoids the use of excessive solvents andproduction of harmful byproducts that are hazardous to the environment,and further avoids the use of endocrine disrupting materials. Therefurther exists a need for coating compositions incorporating such a filmformulation.

SUMMARY OF THE INVENTION

A film forming formulation is provided that includes reaction productsof phosphoric acid with a strained ring alkoxy silane. The phosphoricacid and the strained ring alkoxy silane are present in a molecularratio of from 0.9-3.3:1. The film formulation also includes an aqueoussolvent.

A mold release coating composition is also provided that includes theinventive film forming formulation, a reactive release agent, a base,and an aqueous solvent.

DETAILED DESCRIPTION OF THE INVENTION

The following detailed description is merely exemplary in nature and isin no way intended to limit the scope of the invention, its application,or uses, which may vary. The invention is described with relation to thenon-limiting definitions and terminology included herein. Thesedefinitions and terminology are not designed to function as a limitationon the scope or practice of the invention but are presented forillustrative and descriptive purposes only.

The present invention has utility as a film forming formulation thatavoids the use of excessive solvents, endocrine disruptors, andproduction of byproducts that are hazardous to human health and theenvironment. The inventive formulation uses phosphoric acid as a “seed”or “center” which is utilized as a reactant for strained ring alkoxysilanes that can be reacted under ambient atmospheric conditions in anaqueous solvent in order to form a film forming reaction product.Variation of the stoichiometry of the phosphoric acid relative to thestrained ring alkoxy silanes provides for formulation flexibility. Thereaction products are extremely storage stable and are tunable whenadmixed with other functional materials, providing the ability toproduce a variety of film forming formulations that exhibit a wide rangeof physical properties. This tunability allows for the flexibility toproduce embodiments of the inventive film forming formulation withphysical properties targeted to various specific materials andsubstrates. The present invention also has utility as a mold releasecoating composition incorporating the inventive film formingformulation.

It is to be understood that in instances where a range of values areprovided that the range is intended to encompass not only the end pointvalues of the range but also intermediate values of the range asexplicitly being included within the range and varying by the lastsignificant figure in the range. By way of example, a recited range from1 to 4 is intended to include 1-2, 1-3, 2-4, 3-4, and 1-4.

In at least one embodiment, the inventive film forming formulationincludes reaction products of phosphoric acid with a strained ringalkoxy silane, of which γ-glycidoxy trialkoxy silanes represent a subsetof such silanes operative herein, which are reacted under ambientatmospheric conditions in an aqueous solvent and avoids the use ofexcessive solvents, endocrine disruptors, and production of byproductsthat are hazardous to human health and the environment. It isappreciated that the phosphoric acid and the strained ring alkoxy silaneare present in a molecular ratio of from 0.9-3.3:1. It is furtherappreciated that variation of the molecular ratio of the phosphoric acidrelative to the strained ring alkoxy silane provides flexibilityallowing the inventive formulation to be tuned to achieve desiredphysical properties relative to various targeted substrates andmaterials. By way of non-limiting example, embodiments of the inventivefilm forming formulation have particular utility as basic materials foruse in mold release compositions for elastomers and other moldingmediums. It is appreciated that the inventive formulation has a pH ofbetween 3.0 and 8.0. It is also appreciated that adjustment offormulation pH within the range of 3.0 to 8.0 provides another mode oftunability. It is further appreciated that another mode of tunability ofthe inventive film forming formulation may also be provided by alteringthe types of alkoxys of the strained ring alkoxy silane. A strained ringalkoxy silane operative herein is a monomer or oligomer that typicallyhas an average molecular weight of less than 4,000 Daltons having aformula (I):

(OCH₂CH)—R¹—X—R²—Si—(R³)_(a)(OR⁴)_(3−a)  (I)

where R¹ is C₁-C₄ alkyl, an aromatic, a heteroaromatic, or together with(OCH₂CH) forms (OC₆H₉); X is a nullity or oxygen, R² is C₂-C₆ alkyl, anaromatic, or a heteroaromatic; R³ in each occurrence is independentlyC₁-C₆ alkyl, a is an integer of 0 to 2, inclusive; R⁴ in each occurrenceis independently C₁-C₆ alkyl or (C₁-C₄ alkyl)-O—(C₁-C₄ alkyl), where thealkyl ether groups need not be alike. It is appreciated that an alkyl asused herein is linear, branched or cyclic with the proviso that cyclicalkyls are C₄-C₆. Strained ring alkoxy silanes operative hereinillustratively include 2-(3,4 epoxycyclohexyl) ethyltrimethoxysilane,3-glycidoxypropyl methyldimethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyl methyldiethoxysilane,3-glycidoxypropyl triethoxysilane, and combinations thereof. In at leastone embodiment, the phosphoric acid and the strained ring alkoxy silaneof the inventive film forming formulation are present in a molecularratio of 3:1. In at least one preferred embodiment, when present in amolecular ratio of 3:1, the phosphoric acid is present from 20 to 40weight percent of the total weight of the formulation, and the strainedring alkoxy silane is present from 60 to 80 weight percent of the totalweight percent of the formulation. In another preferred embodiment, whenpresent in a molecular ratio of 3:1, the phosphoric acid is present from25 to 35 weight percent of the total weight of the formulation, and thestrained ring alkoxy silane is present from 65 to 75 weight percent ofthe total weight percent of the formulation.

In at least one embodiment, the phosphoric acid and the strained ringalkoxy silane of the inventive film forming formulation are present in amolecular ratio of 3:2. In at least one preferred embodiment, whenpresent in a molecular ratio of 3:2, the phosphoric acid is present from10 to 25 weight percent of the total weight of the formulation, andstrained ring alkoxy silane is present from 70 to 90 weight percent ofthe total weight percent of the formulation. In another preferredembodiment, when present in a molecular ratio of 3:2, the phosphoricacid is present from 15 to 20 weight percent of the total weight of theformulation, and the strained ring alkoxy silane is present from 75 to85 weight percent of the total weight percent of the formulation.

In at least one embodiment, the phosphoric acid and the strained ringalkoxy silane of the inventive film forming formulation are present in amolecular ratio of 3:3. In at least one preferred embodiment, whenpresent in a molecular ratio of 3:3, the phosphoric acid is present from5 to 20 weight percent of the total weight of the formulation, and thestrained ring alkoxy silane is present from 80 to 95 weight percent ofthe total weight percent of the formulation. In another preferredembodiment, when present in a molecular ratio of 3:3, the phosphoricacid is present from 10 to 15 weight percent of the total weight of theformulation, and the strained ring alkoxy silane is present from 85 to90 weight percent of the total weight percent of the formulation.

The use of reactions products of monofunctional glycidoxy functionalalkoxy silane with phosphorus has been found by the inventors toovercome many of the disadvantages of prior art glycidoxy film formingformulation and systems. By way of non-limiting example, it has beenfound that, relative to the prior art, reaction products of theinventive film formulation are formed without the use of excessivesolvents, endocrine disrupting materials, and production of hazardousbyproducts. This has the benefit of reduction of both the production andthe presence of these harmful materials in the inventive film formingformulation—materials that are hazardous to both human health and theenvironment. In at least one embodiment, the reaction products areconcentrated to a total non-volatile content of greater than 2.4 weightpercent of the total weight of the formulation. In at least onepreferred embodiment, the reaction products are concentrated to a totalnon-volatile content of greater than 15 weight percent of the totalweight of the formulation. In still another preferred embodiment, thereaction products are concentrated to a total non-volatile content ofgreater than 30 weight percent of the total weight of the formulation.

A mold release coating composition is also provided. In at least oneinventive embodiment, the mold release coating composition includes theinventive film forming formulation, a reactive release agent, a base,and an aqueous solvent. In at least one embodiment, the coatingcomposition has a pH of between 3.0 and 8.0. In at least one embodimentof the inventive mold release coating composition, a first quantity ofthe phosphoric acid and the strained ring alkoxy silane is present in amolecular ratio of 3:2 and the reaction products of the first quantityare present from 1.0 to 2.5 weight percent of the total weight percentof the composition. In another inventive embodiment, the reactionproducts of the first quantity are present from 1.5 to 2.0 weightpercent of the total weight percent of the composition. In at least oneinventive embodiment, in addition to the first quantity, the moldrelease coating composition has a second quantity of the phosphoric acidand the strained ring alkoxy silane present in a molecular ratio of 3:3with the reaction products of the second quantity present from 1.0 to2.5 weight percent of the total weight percent of the composition. Inanother embodiment the reaction products of the second quantity arepresent from 1.5 to 2.0 weight percent of the total weight percent ofthe composition.

In at least one embodiment, a reactive release agent is provided and ispresent from 1.5 to 2.0 weight percent of the total weight percent ofthe formulation. In at least one inventive embodiment, the reactiverelease agent is a mono epoxide functional release agent. It isappreciated that the inventive mold release coating composition in someapplications functions as a semi-permanent mold release. Semi-permanentin the context of the present invention is intended to define coatingsof the inventive mold release coating composition applied to a moldsurface and which provide for more than one release per application.

In at least one inventive embodiment, the reaction products are agedbetween 12 and 36 months. In another inventive embodiment, the reactionproducts are aged 18 to 24 months. It is appreciated that the agedreaction products allow for the inventive mold release coatingcomposition to be extremely storage stable.

In at least one inventive embodiment, the inventive mold release coatingcomposition includes at least one of an emulsifier, a catalyst, anantimicrobial agent, a filler, a pigment, a dye, a wetting agent, asurfactant, a thickening agent, a thixotropic agent, a siccative, ananti-skinning agent, or combinations thereof.

A thixotropic agent operative in some inventive embodiments of thepresent invention illustratively includes fumed silica, organoclays,inorganic clays, and precipitated silica. Multifunctional alcohols arecommonly used to enhance thixotropic properties.

Fillers operative in the present invention illustratively include talc,mica, alumina trihydrate, calcium sulfate, calcium carbonate, magnesiumsulfate, magnesium carbonate, barium sulfate, and microspheres.

A siccative additive is provided in some inventive embodiments of thepresent invention to regulate the drying speed of the formulation. Asiccative operative in some inventive embodiments of the presentinvention illustratively includes a transition metal carboxylate forwhich medium- to long-chain linear or branched carboxylic acids—mostcommonly 2-ethyl hexanoic acid or various naphthenic acids are used asligands, and combinations thereof. Transition metals typically includecobalt, zirconium, and manganese; and are routinely used in the printingindustry as drying accelerators.

The present invention is further illustrated with respect to thefollowing non-limiting example:

Example 1

A comparative mold release coating composition is compared relative toan inventive mold release composition containing the same reactiverelease agent. The comparative release coating composition is composedof 87 total weight percent deionized water, 11 total weight percent of3-glycidoxypropyl trimethoxysilane (that has been alcoholyzed inacidified water) and 2 total weight percent of mono epoxide functional,polydimethyl siloxane emulsified polymer. The inventive mold releasecomposition is the same as the comparative mold release coatingcomposition except a 3 times stoichiometric amount of phosphoric acidrelative to the 3-glycidoxypropyl trimethoxysilane replaces a likeweight of water.

An article molded of 100 parts VITON®, 3 parts zinc oxide, 30 partscarbon black, 3 parts ethylene/acrylic elastomer and 3 parts or organicperoxide is a difficult to release peroxide cured fluoroelastomer. Thearticle was molded in a cavity that had been coated with the comparativemold release composition. The molded article would not come out of themold and had to be cut out. In contrast, the inventive mold releasecoating composition was applied to a hot mold and the same difficult torelease fluoroelastomer was molded and freely released. The inventivemold release coating composition provided for at least three releases ofthe same fluoroelastomer. The subsequent reapplication (“a touch-up”) ofthe inventive mold release coating composition provided for at leastthree additional releases for each “touch-up”.

While at least one exemplary embodiment has been presented in theforegoing detailed description, it should be appreciated that a vastnumber of variations exist. It should also be appreciated that theexemplary embodiment or exemplary embodiments are only examples, and arenot intended to limit the scope, applicability, or configuration of thedescribed embodiments in any way. Rather, the foregoing detaileddescription will provide those skilled in the art with a convenient roadmap for implementing the exemplary embodiment or exemplary embodimentsand those skilled in the art will recognize that modifications andchanges can be made to the preferred embodiments of the inventionwithout departing from the scope of this invention defined in thefollowing claims.

1. A mold release coating composition comprising: the formulationcomprising reaction products of phosphoric acid with a strained ringalkoxy silane, where the phosphoric acid and the strained ring alkoxysilane are present in a molecular ratio of from 0.9-3.3:1; a reactiverelease agent; a base; and an aqueous solvent.
 2. The composition ofclaim 1 wherein a first quantity of the phosphoric acid and theγ-glycidoxy trialkoxy silane is present in a molecular ratio of 3:2 andsaid reaction products of said first quantity are present from 1.0 to2.5 weight percent of the total weight percent of the composition. 3.The composition of claim 1 further comprising a second quantity of thephosphoric acid and said strained ring alkoxy silane being present in amolecular ratio of 3:3 and said reaction products of said secondquantity being present from 1.0 to 2.5 weight percent of the totalweight percent of the composition.
 4. The composition of claim 1 whereinsaid reaction products of said second quantity are present from 1.5 to2.0 weight percent of the total weight percent of the composition. 5.The composition of claim 1 wherein said reactive release agent ispresent from 1.5 to 2.0 weight percent of the total weight percent ofthe composition.
 6. The composition of claim 1 wherein said reactiverelease agent is a mono epoxide functional release agent.
 7. Thecomposition of claim 1 further comprising at least one of an emulsifier,a catalyst, an antimicrobial agent, a filler, a pigment, a dye, awetting agent, a surfactant, a thickening agent, a thixotropic agent, asiccative, an anti-skinning agent or combinations thereof.
 8. Thecomposition of claim 1 wherein the phosphoric acid and the strained ringalkoxy silane are present in a molecular ratio of 3:1.
 9. Thecomposition of claim 1 wherein the phosphoric acid and the strained ringalkoxy silane are present in a molecular ratio of 3:2.
 10. Thecomposition of claim 1 wherein the phosphoric acid and the strained ringalkoxy silane are present in a molecular ratio of 3:3.
 11. Thecomposition of claim 1 wherein said strained ring alkoxy silane hasthree alkoxy groups that are all the same and all either methoxy orethoxy.
 12. The composition of claim 1 wherein said strained ring alkoxysilane has three alkoxy groups that are each independently one of: amethoxy, an ethoxy, a propoxy, a butoxy, a pentoxy, a hexoxy, a heptoxy,an octoxy, a nonoxy, or a decoxy.
 13. The composition of claim 1 whereinsaid reaction products are concentrated to a total non-volatile contentof greater than 2.4 weight percent of the total weight of theformulation.
 14. The composition of claim 1 wherein said reactionproducts are concentrated to a total non-volatile content of greaterthan 15 weight percent of the total weight of the formulation.
 15. Thecomposition of claim 1 wherein said strained ring alkoxy silane has anaverage molecular weight of less than 4,000 Daltons and has a formula(I):(OCH₂CH)—R¹—X—R²—Si—(R³)_(a)(OR⁴)_(3−a)  (I) where R¹ is C₁-C₄ alkyl, anaromatic, a heteroaromatic, or together with (OCH₂CH) forms (OC₆H₉); Xis a nullity or oxygen, R² is C₂-C₆ alkyl, an aromatic, or aheteroaromatic; R³ in each occurrence is independently C₁-C₆ alkyl, a isan integer of 0 to 2, inclusive; and R⁴ in each occurrence isindependently C₁-C₆ alkyl or (C₁-C₄ alkyl)-O—(C₁-C₄ alkyl).
 16. Thecomposition of claim 1 wherein said strained ring alkoxy silane is2-(3,4 epoxycyclohexyl) ethyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropyl trimethoxysilane,3-glycidoxypropyl methyldiethoxysilane, 3-glycidoxypropyltriethoxysilane, and combinations thereof.